This invention relates generally to the preparation of functional fluids and more specifically to a process for preparing phosphorus ester anti-wear agent containing automatic transmission fluids (ATF) having a reduced break-in period.
Esters of phosphorus acids are used in lubricants to impart anti-wear properties. I have found that in functional fluid applications, such as automatic transmission fluids (ATF), where the esters are used in oil blends containing ashless dispersants of the alkenyl succinimide-succinamide type, the fluids must undergo an extended break-in period before they provide stable dynamic and static torque characteristics.